Development of a 50 kV hydrogen-helium mixed ion beam implanter

Ion implanters have extensively been employed to simulate the irradiation effects of neutrons on relevant nuclear materials. In this study, a 50 kV hydrogen-helium mixed ion beam implanter was developed to generate H2+ and He+ ion beams, with a beam current of 20 µA, while keeping the impurity ion content below 2%. The ions are generated by an antenna-type 2.45 GHz electron cyclotron resonance ion source, and the hydrogen-to-helium ion beam ratio was controlled using two gas mass flow controllers to ensure long time stability of the beam current. As a result, the H2+/He+ ratio, beam size, and homogeneity of the beam spot can be maintained at a stable level. The beam line consisted of four Wien filters, a movable dual-slit plate, and an accelerator tube. The experimental results demonstrated successful transport of more than 20 µA of H2+ and He+ ion beams onto the target, with a beam axis deviation of less than 0.5 mm.

Endovascular Release of a 50-Year-Old Adams-Deweese IVC Clip to Facilitate Percutaneous Repair of Mitral Valve Regurgitation

Percutaneous mitral valve (MV) repair using MitraClip requires large-caliber venous access. We describe a patient with a ligated inferior vena cava due to an Adams-DeWeese clip placed 50 years prior, who had progressive shortness of breath and lower extremity symptoms secondary to severe mitral regurgitation and chronic iliocaval deep venous thrombosis. Due to comorbidities, MitraClip was recommended over surgery for MV repair. Caval luminal gain was required to facilitate endovascular access for the MitraClip system. Stent-mediated release of the inferior vena cava clip allowed successful passage of the delivery sheath from the common femoral vein to MV and subsequent valve repair.

The Performance of Hg0.8Cd0.2Te Photodetectors by Using Photo Surface Treatment

The principal aim of this paper is to propose an easy, vapor phase, and reproducible photo surface treatment method to improve the device performance of the Hg0.8Cd0.2Te photoconductive detector. Experimental results, including Auger electron spectroscopy (AES), MIS leakage current, 1/f noise voltage spectrum, 1/fknee frequency, responsivity Rλ, and specific detectivity D* for stacked photo surface treatment and ZnS or CdTe passivation layers are presented. By using this method, we found that there is no accumulation of Hg in the oxide/HgCdTe interface regions. Since the photo chemical vapor native oxidation is a dry oxidation method deposited at a low temperature, it can effectively suppress the Hg enhancement and the Cd depletion effects and thus obtain a high quality interface. We also found that the photo surface treatment in combination with thermally eveporated ZnS or CdTe layer would shift the 1/fknee under 100Hz in an electrical field under 50 V/cm, reduce the noise power spectrum, and achieve a lower surface recombination velocity S of 300 cm/sec as well as a high D* of 3 × 1010 cm [Formula: see text] for blackbody radiation. It was also found that HgCdTe photoconductor passivated with stacked layers shows improved interface properties when compared to the photoconductor passivated with a single passivation layer.

Ultraviolet ZnO nanorod photosensors

This study fabricates and characterizes ultraviolet (UV) photosensors with ZnO nanorods (NRs). The NR arrays were selectively grown in the gap between interdigitated (IDT) electrodes of devices using hydrothermal solution processes and a lithography-based technique. Compared with a conventional ZnO photosensor without NRs, the proposed UV NR photosensors have much higher photoresponse in the UV region. Additionally, the photoconductive gain of an NR photosensor increased as UV illumination time increased; it varied at 34.45-5.32 x 10(2) under illumination by 18.28 mW/cm(2) optical power. Consequently, the substantial photoconductive gain can be attributed to high surface-to-volume ratio of ZnO NRs. The high density of hole-trap states on NR surfaces lead to a persistent photoconductivity (PPC) state, promoting the transport of carriers through devices.

Intracranial pressure fluctuation during hemodialysis in renal failure patients with intracranial hemorrhage

Coagulopathy in renal failure patients often makes them vulnerable to intracranial hemorrhage. Emergency decompression to remove the hematoma and to stop bleeding is always indicated. After the surgery, hemodialysis (HD) should be arranged to maintain the BUN/Cr. level, and I/O balance. During HD, intracranial pressure in all of the patients in this study fluctuated. This phenomenon always resulted in neurological deterioration in acute or chronic renal failure. We present intracranial pressure (ICP) changes during HD in five acute or chronic renal failure patients with intracranial hemorrhage. They all underwent craniectomy or craniotomy with ICP monitors implantation. Different HD protocols were arranged for these patients and then we observed clinical results. ICP elevated during HD and resulted in severe brain swelling. This situation was one of the clinical presentations of dialysis disequilibrium syndrome (DDS). Four patients died because of this complication and one survived. ICP fluctuation seemed to be correlated with the fluid amount and frequency of HD. The prevalence and pathophysiology of DDS remain unclear. Renal failure patient with intracranial hemorrhage may be complicated with DDS when HD was performed. An attempt to reduce the fluid amount and to increase the frequency of HD might help these patients.

Effect of hyperbaric oxygen on patients with traumatic brain injury

Hyperbaric oxygen therapy (HBOT) is the medical therapeutic use of oxygen at a higher atmospheric pressure. The United States Food and Drug Administration have approved several clinical applications for HBOT, but HBOT in traumatic brain injury (TBI) patients has still remained in controversial. The purpose of our study is to evaluate the benefit of HBOT on the prognosis of subacute TBI patients. We prospectively enrolled 44 patients with TBI from November 1, 2004 to October 31, 2005. The study group randomly included 22 patients who received HBOT after the patients' condition stabilization, and the other 22 corresponding condition patients were assigned into the matched control group who were not treated with HBOT. The clinical conditions of the patients were evaluated with the Glasgow Coma Scale (GCS) and Glasgow Outcome Scale (GOS) before and 3 to 6 months after HBOT. The GCS of the HBOT group was improved from 11.1 to 13.5 in average, and from 10.4 to 11.5 (p < 0.05) for control group. Among those patients with GOS = 4 before the HBOT, significant GOS improvement was observed in the HBOT group 6 months after HBOT. Based on this study, HBOT can provide some benefits for the subacute TBI patients with minimal adverse side effects.

Nosocomial blood-stream infection in patients with end-stage renal disease: excess length of hospital stay, extra cost and attributable mortality

Patients with end-stage renal disease undergoing haemodialysis are at high risk of nosocomial blood-stream infection (BSI), but data on the associated costs in this patient population are not available. Therefore, we conducted a retrospective matched (1:2) case-control study of such patients undergoing haemodialysis from January 1998 to December 1998 in a medical centre in southern Taiwan to determine the excess length of hospital stay, attributable mortality, and the extra cost caused by nosocomial BSI. The excess length of hospital stay was 30 days for cases vs. 16 days for controls (P<0.001), the mortality rate was 26.3% for cases vs. 0 for controls (P=0.003) (attributable mortality being 26.3%), and the median of overall costs was 131,584 dollars NT for cases vs. 65,282 dollars NT for controls (P<0.001). Based on these findings, we believe that an effective programme to minimize nosocomial BSI in this patient population would greatly reduce their medical and economic burdens.

[Quantitative analysis of the cellular DNA and RNA contents of hydatidiform mole and its clinical significance]

The cellular DNA and RNA contents of 152 patients with hydatidiform moles (69 benign and 83 malignant) were analysed by flow cytometry (FCM), and strict follow-up was implemented. The chorionic villi of twelve cases in early pregnancy were used as normal control and another 12 cases of choriocarcinoma as positive control. Retrospective as well as prospective studies were conducted. The results showed that the accuracy rates of diagnosis of DNA aneuploid and RNA were respectively 66.7% and 82.6% in benign moles, 68.7% and 81.9% in invasive moles. Statistically the RNA parameter was significantly more sensitive the DNA parameter (P < 0.05). Analysis with both RNA and DNA parameters in predicting malignancy, the accuracy rate was 94.0%. Our study suggests that both the aneuploidy DNA and RNA contents may be important indicators for forecasting malignant change. The RNA parameter is more sensitive than the DNA parameter, and the use of both parameters is more accurate than either one alone. In addition, the concept of "standard DNA index" is raised.

Flow cytometric analysis of cellular DNA and RNA contents of hydatidiform mole. Two significant parameters indicating malignant nature and prognosis

The cellular DNA and RNA contents of trophoblastic tissue of 86 patients with trophoblastic disease and chorionic tissue of 10 patients in early pregnancy were analysed by flow cytometry (FCM) and strict follow-up was carried out. The result showed the rate of accurate diagnosis by DNA and RNA determinations were 60.0% and 85.7% respectively in benign moles; 86.7% and 86.7% in invasive moles; and 100% and 100% in choriocarcinoma. Statistically the pseudopositive percentage of RNA was clearly lower than that of DNA (0.01 < P < 0.05). In addition, the trophoblastic cells in curetted molar tissue and the uterine tissue later proved by surgery of 10 invasive moles were simultaneously assayed for comparing their DNA and RNA contents, showing statistical significance (P < 0.001). The DNA and RNA contents in different cellular cycles were analysed by FCM and there was no statistical significance among benign, malignant moles and choriocarcinoma (P > 0.05). Our study suggests that aneuploidy DNA content may be an indicator for malignant tendency and the RNA parameter rather than DNA is more sensitive for the prognosis of hydatidiform mole.

Delivery by direct intrauterine transfer of gametes

A nurse, 27, primary sterility for 5 years, had normal menstruation, normal size of uterus anterior. HSG: Rt. tube was not visible, Lt. tube slightly enlarged at ampulla. Ovaries were over-stimulated by clomiphene, HMG and hCG.8 ova were taken through vaginal aspiration under B-mode ultrasound scanning. Direct introduction of ova and washed sperms simultaneously into the uterus on Sept. 19, 1991 resulted in successful single pregnancy up to 36(+1) weeks. A 2 250 g normal baby boy was delivered on May 15, 1992 spontaneously. The base and prospect of this manoeuver are discussed with a reference to Craft's procedure.

[Delivered by direct intrauterine transfer of gametes]

A nurse, 27, primary sterility for 5 years with normal pelvic findings. Hysterosalpingogram showed right tube not visualized, and impatent, left tube with slight enlargement at ampulla. Her last menstrual period was September 5, 1991. Ovaries hyperstimulated by clomiphene, HMG and hCG, and 8 ova taken through vaginal aspiration under B scanning on September 19, 1991. Ova and washed sperms were directly introduced into uterine cavity simultaneously. It turned out to be a successful clinical pregnancy, carried on smoothly up to 36(+1) weeks. She spontaneously delivered a healthy male infant weight 2250 grams on May 15, 1992.

[Embolus formation using bismuth polyurethane for tubosterilization observation of 259 cases]

A 50% solution of bismuth polyurethane in absolute alcohol, which remains in a liquid state at 70 degrees C and solidifies at body temperature within a few minutes, was used to form embolus in the fallopian tubes for the purpose of tube-sterilization. This compound is non-caustic and proves to be bioadaptable. A modified Foley's catheter was used to introduce the solution into the lumens of the tube by way of the uterine cavity in 259 cases. A 24 month follow-up by life table method was carried out, and 26 were pregnant with a pregnancy rate of 10.0%. The number of successful operation at the first attempt was 234 with 18 cases pregnant (7.7%). The recanalization rate of the tubes within 24 months was 11.4% including those of pregnancy. There was little side reactions postoperatively. A polyethylene 2 way tube with a rubber bulb for instillation of the bismuth polyurethane had been made on October 1990. Ways of improving the successful rate were mentioned. The authors believe that this is a useful procedure of tubo-sterilization, which is easily accepted by the patients and easily carried out by the medical personnel.

[Prediction of the malignant tendency of hydatidiform mole by determination of DNA content]

The cellular DNA content of paraffin-embedded molar tissue blocks obtained from the first curettage was measured by flow cytometry in 64 cases of hydatidiform mole. Of these 64 cases 32 developed malignant changes and 32 remained persistently benign during a period of follow-up of 0.5 to 7.5 years. The proportion of aneuploid was 59.4% in patients demonstrating malignant changes and 34.4% in those with persistent benign diseases. The difference was statistically significant (P less than 0.05). This preliminary result suggests that DNA aneuploid may be used as a parameter for the prediction of possible malignant changes and selecting of indications for prophylactic chemotherapy.

Coding assignments of each mRNA synthesized in vitro and protein components of CPV of silkworm Bombyx mori

The coding properties of each mRNA synthesized in vitro of CPV have been examined. The mRNAs were separated by polyacrylamide gel electrophoresis and isolated from the gel slices. The individual mRNA was then translated into the wheat germ cell-free protein synthesizing system. The products of translation were analyzed by the immuno-reaction with the 125I-IgG of each of the five electrophoretic protein components of CPV. The coding assignments were deduced on the basis of the immuno-reaction as follows: mRNA1, mRNA3 and mRNA9 encode group P1 of viral proteins, mRNA2 and mRNA6 encode group P2 and P3, respectively. mRNA7 and mRNA8 encode group P4 while mRNA9 encode group P5. There are more than 10 polypeptides in the CPV virion as demonstrated by two-dimensional electrophoresis.

Wavelength and temperature dependence of RAPD aser detectors

Wavelength and temperature-dependent characteristics of silicon reach-through avalanche photodiodes (RAPD) are studied using the modified Baraff's theory. The temperature and wavelength regions discussed are 100-500 K and 0.655-1.06 microm, respectively, for Si photodetectors. The effects of breakdown voltage, depletion region width, and efficiency on the avalanche region width are widely studied. Both n(+) (front) side and p(+) (back) side illumination are also considered. The noise equivalent power is significantly reduced with light incident on the p(+) surface with little sacrifice of efficiency. An RAPD structure is proposed in which the direction of radiation incidence causes photogeneration to precede avalanche multiplication reducing the multiplication noise substantially. This result should be useful in the design of RAPD laser detectors.

Characteristics of P-I-N laser detectors: their dependence on wavelength and temperature

Wavelength and temperature-dependent characteristics of silicon P-I-N laser detectors are studied using the modified Baraff theory. Both the electron or hole injection effect and photogeneration effect are considered in the calculation of the power spectral density of multiplication noise and efficiencies. The results thus obtained are compared with previous papers where the photogeneration effect was neglected.